Endless jaw chain self-clamping winch

ABSTRACT

The rope extending through the device is clamped in a groove of substantially semi-circular or part-circular cross sectional contour, formed in the outer periphery of a pulley, along a predetermined arc of this pulley, by clamping jaws of curved longitudinal configuration and part-circular cross-sectional contour, said clamping jaws being adapted to move along with the rope during the travel thereof through the device, said clamping jaws being carried by an endless chain meshing with at least one circular set of teeth rigid with said pulley, suitable means being provided for automatically exerting against the ropeengaging jaws a clamping force varying as a function of the tension of the taut run of said rope.

United. States Patent Levardon 1 Apr. 24, 1973 I ENDLESS JAW CHAIN SELF- CLAMPING WINCH Primary Examiner-Harvey C. Homsby [75] Inventor: Raymond Levardon, Paris, France Atwmey limon & Limo [73] Assignee: Tractel S.A., Paris, France [57] ABSTRACT [22] Filed: Jan. 24, 1972 The rope extending through the device is clamped in a Appl. No.: 220,271

groove of substantially semi-circular or part-circular cross sectional contour, formed in the outer periphery of a pulley, along a predetermined arc of this pulley, by clamping jaws of curved longitudinal configuration and part-circular cross-sectional contour, said clamping jaws being adapted to move along with the rope during the travel thereof through the device, said clamping jaws being carried by an endless chain meshing with at least one circular set of teeth rigid with said pulley, suitable means being provided for automatically exerting against the ropes-engaging jaws a clamping force varying as a function of the tension of the taut run of said rope.

5 Claims, 6 Drawing Figures Patented April 24, 1973 3,729,173

3 Sheets-Sheet l Patented April 24, 1973 3 Sheets-Sheet 2 ENDLESS .IAW CHAIN SELF-CLAMPING WINCH FIELD OF THE INVENTION The present invention relates to a winch adapted to control the travel of a hoisting or traction rope through the device in either direction, for pulling, hauling in, heaving or hoisting a load by pulling the rope, or alternatively for releasing or lowering a load with a controlled holding of the rope.

DESCRIPTION OF THE PRIOR ART I Since the winch operation consists in causing a relative movement between the rope and winch casing, it is clear that the latter can be anchored to a fixed point for acting upon a movable rope having the load attached to or suspended from one of its ends, or in contrast thereto the winch may be adapted to travel along a stationary rope for driving a load suspended from the winch.

SUMMARY OF THE INVENTION The winch according to this invention is characterized essentially in that the rope extending through the device is clamped in a groove of substantially semicircular or part-circular cross sectional contour, formed in the outer periphery of a pulley, along a predetermined arc of this pulley, by clamping jaws of curved longitudinal configuration and part-circular cross-sectional contour, said clamping jaws being adapted to move along with the rope during the travel thereof through the device, said clamping jaws being carried by an endless chain meshing with at least one to apply to said pulley a driving torque in the hoisting direction and a resistant torque in the lowering or release direction, i.e. in the direction in which the pulley tends to rotate under the influence of the winch load.

The clamping of the rope to said pulley by means of curved jaws driven directly from said power pulley is attended by a twofold advantage i only a relatively moderate force is required for pressing the rope against the pulley by means of said curved jaws, since the rope-retaining force of these jaws is almost as effective as the pulley force for the same purpose, and

The rope-receiving grooves, whether on the pulley or in the clamping jaws, can be given a part-circular or semi-circular cross-sectional shape whereby the rope wear is reduced considerably and better distributed in comparison with a trapezoidal groove associated with presser rollers engaging the rope directly and therefore without any rope retaining action, as in known prior art structures.

The clamping of the jaws against the rope as a function of the tension of the taut run of the rope is advantageously obtained by using rollers engaged by the travelling jaws driven from the power pulley and responsive to a radial clamping force exerted through the medium of a multiplying lever associated with a rod interposed between this lever and the shaft of a deflection pulley responsive to the tension of the taut run of the rope.

According to a preferred form of embodiment of this invention the winch constituting the subject-matter thereof is caracterized by the combination of the following component elements l. a power or driving pulley having a peripheral groove of part-circular cross-sectional configuration, engaged along one fraction of the pulley circumference by the rope extending through the device 2. an endless, non-tensioned chain supported by a pair of loose guide pulleys or by a rope inlet and outlet guide, said chain consisting of curved clamping jaws constituting the links thereof and so disposed as the engage by turns the rope winding section on the slack rope run side V 3. a pair of circular lateral flanges formed with spaced notches, concentric to and rigid with said pulley on either side of its groove for driving or retaining said chain through the meshing engagement of the chain link pins with said notches 4. a stress multiplying device interposed between a pulley responsive to the tension of the taut run of the rope, and a rocker adapted to distribute equal clamping forces among the rollers acting on said clamping jaws in order to press same against the rope with a force varying as a function of the rope tension and therefore of the load controlled through said rope.

BRIEF DESCRIPTION OF THE DRAWING A clearer understanding of this invention will be had if reference is made to the accompanying drawing illustratingdiagrammatically by way of example a typical form of embodiment of the invention. In the drawing FIG. 1 is a vertical section showing the winch according to this invention I FIG. 2 is a fragmentary radial section showing on a larger scale the pulley, the jaw chain and a guide roller, the section being taken along the line 11-11 of FIG. 1

FIG. 3 is a longitudinal sectional view taken along the line III--lII of FIG. 1, alsoon a larger scale FIG. 4 is a diagrammatic view illustrating a typical form of embodiment of the rocker for distributing the clamping forces among the rollers FIG. 5 is a cross section taken along the line V-V of FIG. 4, and

FIG. 6 is a longitudinal section taken along the line VI--VI of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT The winch illustrated in FIG. 1 comprises a casing l in which the shaft 2 of a power or driving pulley 3 is journalled this pulley 3 has a peripheral groove 4 of part-circular cross-sectional configuration, adapted to be engaged by the rope 5 extending through the device. The two runs of the rope which emerge from the casing 1 through apertures provided to this end comprise the taut run 6 and the slack run 7. It may be assumed for instance that the taut run 6 is connected to a load to be displaced, while the casing 1 is anchored to a fixed point or structure, or alternatively that the taut run 6 is anchored to a fixed point or structure while the load is suspended from the casing 1, for example at 8. In either case, the operation of the device is the same, since it depends only on the relative movements of the winch with, respect to the rope therefore, in the following disclosure, it is not deemed necessary to make a discrimination between the two modes of operation.

The power pulley 3 is driven from any suitable source of power (not shown) which is no part of the present invention.

An endless chain 13 is adapted to move through the casing l and guided to this end by a pair of side guards or lateral flanges ll rigid with a curved guide channel 12, the endless circuit of said chain 13 being completed externally of this channel 12. Between its successive pivot or link pins 14 the chain 13 carries a plurality of convex clamping jaws 15 having a curvature matching that of the pulley groove 4 moreover, these jaws 15 have a concave part-circular cross-sectional contour 17 on their concave clamping face 16, said contour 17 being adpated to co-act with the matching contour of said groove 4 of pulley 3 for clamping the rope 5.

On either side of its groove 4 the pulley 3 carries a pair of concentric circular flanges 18 formed with spaced notches l9'of which the relative spacing corresponds to the pitch or longitudinal spacing of chain link pins l4-so as to receive said pins 14 along one fraction of the endless chain passing over the pulley 3, so

that the chain is driven or retained, accordingto the desired mode of operation of the device, by said pulley 3.

The convex face 20 of each jaw 15 opposite to said clamping face 16 constitutes a race or ramp engageable by three presser rollers 21, 22 and 23 registering with the pulley 3 and supported by pins 24, 25 and 26 urged towards said pulley 3 by a stress-distributing rocker 27 supporting this last-named pin 26 and aligned pins 28, to which a strap 29 supporting the other pins 24 and 25 is pivoted. This rocker 27 is pivoted through a pin 30 to a link .31 pivotedin turn to a multiplying lever 32 fulcrumed about a fixed pin 33. This lever 32 is connected througha rod 34'to the shaft of a deflector pulley 35 over which the taut run 6 of the rope is passed.

Now the mode ,of operation of this winch will be described briefly. Assuming the pulley 3 is inoperative and rope run 6 tensioned by a load or otherwise, the rope will tend to slip through the winch towards its taut run passing over the deflector pulley 35 so that the latter tends to be pushedby the rope of which the taut run 6 tends to assume a straight. course. The force thus applied by said taut run 6 to pulley 35 is transmitted via rod 34 to the multiplying lever 32 which, through link 31, urges the rocker 27 of presser rollers 21, 22 and 23 against the jaws l5 registering therewith, so that these jaws engage the rope section 5 received in the groove 4 of pulley 3. The force thus exerted by the rollers is subordinate to the tension of rope run 6 and will thus prevent any slipping of the rope in groove 4 of pulley 3, irrespective of the tension exerted on said rope 5 by the load or otherwise.

Now if the pulley 3 is driven for rotation in the direction of the arrow of FIG. 1, the taut run 6 will adhere more strongly to the groove 4 of pulley 3, and this condition corresponds to th hauling, pulling or hoisting of a load. The movement of pulley 3 is attended by thecirculation of the endless jaw chain 13 through the engagement of this chain in notches 19, so that the jaws 15 pressed against the rope engage by turns the pulley3 with precision while clamping the rope 5 as they pass between the pulley 3 and the presser rollers 21, 22 and 23. Since on the one hand the jaws 15 have a longitudinal contour corresponding to the rope curvature and a transverse contour corresponding to the cross-sectional contour of this rope, and since on the other hand said jaws follow the movement of rope 5, they partake in the rope retaining effort in conjunction with the groove 4 of pulley 3, thus reducing the force necessary for applying the rope into said groove 4 and therefore the rope distortion, so that the useful life of the rope is extended considerably.

When the pulley 3 is driven in the other direction, i.e. counter-clockwise as seen in FIG. 1, the rope 5 will travel through the device in the direction in which it is urged by the load, and remains still strongly bound to pulley 3 in the same fashion as a consequence of the clamping action exerted by jaws 15, so that any rope slip in relation to pulley 3 is safely precluded. Under these conditions, th load cannot fall freely, since it is retained by the pulley of which the movement can be controlled through any suitable and conventional means, for example means for limiting its velocity or rotation.

One of the two holes of each clamping jaw 15 which receives the pivot pins has an elongated configuration to permit a certain variation in the distance between centres as a function of the variation in the jaw chain winding diameter on pulley 3, according to the compression exerted on the rope as a consequence of this clamping action. Each chain link comprises a strapshaped end 36 and a tenon-shaped end 37, the enlongated hole being formed'perferably in'the tenon in order better to support the pin. This arrangement is illustrated in FIGS. 2 and 3 showing thestrap 36 comprising aligned circular holes 38 and adapted to receive between its arms the tenon of the adjacent jaw which comprises an elongated hole 39. Each pivot pin 14 engaging both an elongated hole 39 and the pair of aligned holes 38 projects from both sides of the interconnected jaws l3 and carries at each end a roller 40 adapted on the one hand to engage a corresponding notch 19 for causing the chain 13 to be driven from pulley 3 and on the other hand to roll on the side ramps 1 1.

FIGS. 4, 5 and 6 illustrate details of the rocker 27 designed for distributing the clamping efforts among the three rollers. This rocker 27 is pivoted through pins 41 aligned with the corresponding pivot pin 25 to a strap 42 pivoting in turn about a pivot pin 43 secured to the casing 1. It is clear that the radius of the pulley passing through the axis 28 forms equal angles with the radii passing through the pivot pins 24 and 25, and that the radius passing through the aligned pivot pins 41, 30

forms equal angles with those passing through pivot pins 24, 26. Under these conditions, the clamping force transmitted through pin 28 is twice that transmitted invention which through pin 26 and since this force is divided into two equal forces exerted on the roller pins 24, 25, it will be seen that the application of a radial force through the rocker pin 30 is attended by the transmission of equal clamping forces to the three rollers.

To complete the above description it may be emphasized that the travel of the endless chain 13 along the guide channel 12, in lieu of its passage over a pair of loose pulleys possibly disposed at the inlet and outlet sides of power pulley 3, affords a more compact winch construction due to the reduction in the number of chain links. This construction requires a wavy contour of the guide ramps 11 in order to ensure a regular meshing engagement between the chain 13 and the power pulley 3. This meshing engagement is subordinate to a minimum, constant rise of the outer run of the chain. Th angular pitch of the waves constituting the contour of said guide ramps 11 corresponds to the angular pitch of chain 13 following the arcuate guide channel 12 rigid with casing 1.

Inside the curve of said guide channel 12 a tension spring 44 having one end anchored at 45 and its opposite end attached to the clamping effort multiplying lever 32 urges the clamping rollers 21, 22 and 23 against their races, notably when no' load is supported by the rope or the device.

The reference numeral 46 designates an arcuate elongated hole centered to the axis of the power pulley 3 and formed in the two side flanges of easing l for receiving the ends of the shaft of deflector pulley 35 which are provided to this end with a pair of loose rollers.

A stationary rope guide member 47 having the same curvature as the power pulley 3 is provided in the largest angular space available between the deflector pulley 35 and the inlet means for guiding the endless chain 13 towards the power pulley 3 this member 47 is disposed between the two notched flanged 18 of this pulley 3 and prevents the rope from escaping from the pulley groove 4.

Beyond the chain outlet guide the rope is guided by tubular means 48 adapted to restore the contact between the slack run of the rope and the outer portion of the endless chain 13.

Of course, various modifications and variations may be brought to the typical form of embodiment of this is described hereinabove with reference to the accompanying drawing, without inasmuch departing from the scope of the invention as set forth in the appended claims.

What I claim is 1. A winch with limited rope travel, wherein the rope is adapted to be clamped radially in the groove of a power pulley along a certain arc thereof by the links of an endless chain which are urged in turn against said rope by roller means as a consequence of the winch load, said chain adapted to press said rope in the pulley groove being rotatably solid with said pulley, through the meshing engagement of the pivot pins of the chain links with notches formed in an annular member rigid with said power pulley, whereby said chain can partake in the driving and retaining of said rope in conjunction with the pulley and the groove of said pulley is given a semi-circular cross-sectional contour improving its ro e-en a in surface while avoidin an wed in of saizl rop l hi lh might involve damaggs th eretm so %hat at the same time and given a same load the force exerted by said rollers on the chain can be reduced accordingly.

2. Winch as set forth in claim 1, wherein said chain links comprises at one end an elongated hole for the interconnecting pin, in order to ensure a constantly uniform angular velocity of said link and therefore of the rope, nothwithstanding the possible wear and distortion thereof, thereby avoiding any relative slip between the link and the rope while ensuring a flexible meshing engagement between the link pins and the notches of the annular member rigid with said power pulley.

3. Winch as set forth in claim 2, wherein inlet and outlet guide members are provided for the endless chain, said guide members consisting of a pair of stationary ramps engageable by the rollers of the chain link pins, said ramps having a corrugated contour wherein the waves have an angular pitch corresponding to the angular pitch of the links so that a constant slack equally distributed throughout the chain length is obtained while guiding said chain along a path smaller than that corresponding to a simply circular guiding path, whereby the number of chain links and the overall dimensions of the winch can be reduced accordingly.

4. Winch as set forth in claim 3, wherein a deflector pulley connected to a stress multiplying lever controlling the rope presser rollers and receiving the rope along one fraction of its groove is adapted as a consequence of the rope deflection to exert on said rollers a clamping effort proportional to the load, thus avoiding any reaction between the casing and the clamping means, whereby the possible engagement of said casing with an obstacle during the winch operation in the release or lowering direction will not cause a reduction in the effort exerted on the rollers.

5. Winch as set forth in claim 4, wherein the chain links are shaped to constitute clamping jaws of which the clamping face has the contour of a semi-circular groove, the opposite face being shaped to constitute a continuous circular race engageable by said clamping rollers. 

1. A winch with illimited rope travel, wherein the rope is adapted to be clamped radially in the groove of a power pulley along a certain arc thereof by the links of an endless chain which are urged in turn against said rope by roller means as a consequence of the winch load, said chain adapted to press said rope in the pulley groove being rotatably solid with said pulley, through the meshing engagement of the pivot pins of the chain links with notches formed in an annular member rigid with said power pulley, whereby said chain can partake in the driving and retaining of said rope in conjunction with the pulley and the groove of said pulley is given a semi-circular cross-sectional contour improving its rope-engaging surface while avoiding any wedging of said rope which might involve damages thereto, so that at the same time and given a same load the force exerted by said rollers on the chain can be reduced accordingly.
 2. Winch as set forth in claim 1, wherein said chain links comprises at one end an elongated hole for the interconnecting pin, in order to ensure a constantly uniform angular velocity of said link and therefore of the rope, nothwithstanding the possible wear and distortion thereof, thereby avoiding any relative slip between the link and the rope while ensuring a flexible meshing engagement between the link pins and the notches of the annular member rigid with said power pulley.
 3. Winch as set forth in claim 2, wherein inlet and outlet guide members are provided for the endless chain, said guide members consisting of a pair of stationary ramps engageable by the rollers of the chain link pins, said ramps having a corrugated contour wherein the waves have an angular pitch corresponding to the angular pitch of the links so that a constant slack equally distributed throughout the chain length is obtained while guiding said chain along a path smaller than that corresponding to a simply circular guiding path, whereby the number of chain links and the over-all dimensions of the winch can be reduced accordingly.
 4. Winch as set forth in claim 3, wherein a deflector pulley connected to a stress multiplying lever controlling the rope presser rollers and receiving the rope along one fraction of its groove is adapted as a consequence of the rope deflection to exert on said rollers a clamping effort proportional to the load, thus avoiding any reaction between the casing and the clamping means, whereby the possible engagement of said casing with an obstacle during the winch operation in the release or lowering direction will not cause a reduction in the effort exerted on the rollers.
 5. Winch as set forth in claim 4, wherein the chain links are shaped to constitute clamping jaws of which the clamping face has the contour of a semi-circular groove, the opposite face being shaped to constitute a continuous circular race engageable by said clamping rollers. 